ISSN: 2277 – 9043 International Journal of Advanced Research in Computer Science and Electronics Engineering (IJARCSEE) VOLUME 8, ISSUE 11, NOVEMBER 2019 All Rights Reserved © 2019 IJARCSEE 50 Literature Review on the Diabetic Retinopathy in Retinal Images Abstract— Diabetes is one of the most harmful disease of our age and that’s because of the fast and unhealthy pace of our lives. Numbers are still rising and the number of people getting diabetes is increasing around the world, one of the most recognizable side effects of Diabetes is Diabetic Retinopathy that might lead to total loss of sight in the diabetic patients and that’s if it is not detected and medicated early, for the importance of early detection of this disease there is a great effort in the literature to early detect Diabetic Retinopathy, a literature review is introduced in this report to cover the different aspects of retinopathy and its detection methods. In this review we try to cover a great part of the literature and our review based on two parts: the first part about the detection of the lesions of the Diabetic Retinopathy including hemorrhages, microaneurysm and exudates. The second part is about the measuring of different severity level of diabetic retinopathy and its detection and classification systems. Keywords—Diabetic retinopathy, Medical Images, Retinal images, Feature extraction, Segmentation. I. INTRODUCTION Diabetes which is scientifically known as diabetes mellitus (DM) is a disease usually caused by a deficiency at the pancreas that leads to low level of the insulin production which is the hormone responsible of maintaining the sugar level in the blood. The lack of the insulin production will definitely results in the increase of the glucose concentration in the blood, which leads to the damage in multiple organs of the human body , specifically in the vessels and nerves specially retinal vessels [1] . According to the ADA (American Diabetes Association) , more than 25.8 million of the adults and children which utilize 8.3% of the population in the United States diabetes patients [1] , And these numbers will keep increasing because of the changing life style and the reduced physical activity. The study in [3] was conducted on 91 countries around the world predicted a jump in the numbers of adults with diabetes reaching a rate of 69% in developing countries and a rate of 20% in developed countries in the next few years . Diabetes is a silent disease the detection is related to the appearance of the multiple primary and secondary symptoms , and without the full conscious of the patient the disease will cause more damage to the retinal vessels causing defection to the eyes and leading in some cases to the total loss of sight . One of the famous side effects of diabetes is the diabetes retinopathy or Diabetic Retinopathy (DR) that can causes severe eyes damage and blindness for diabetic people, commonly DR is resulted from long-term diabetes, Diabetic Retinopathy comes usually as result of the leakage of proteins and other fluids from retina vessels which causes the formation of exudates on the surface of the retina that leads to vision impairment. Researchers have shown that the chance of contracting a diabetic retinopathy rise in in a person with more than 10 years of diabetes in 80% [4]. Nowadays this health burden affects the life of more than 100 million people worldwide , a study conducted between1990 and 2010 estimates that DR-related blindness and vision problems increased by 64% and 27% , respectively [5]. Diabetic Retinopathy (DR) considers as very dangerous eye disease because people with diabetic retinopathy might not feel any symptoms in the beginning of the disease, the patient will not feel any symptoms until a serious damage happened to the retina, these symptoms includes: vision Blurring , nighttime seeing difficulties , blood vessels swelling in the eye, fluid leakage , growing abnormal blood vessels on the retina’s surface. As the problem getting worse , a new blood vessel grows on the retina which blurs the vision. Unfortunately, the damage to the retina happened to be in the two eyes, so the vision is changed gradually in the diabetic patients. In Fig 1 the difference between the vision of a patient with diabetic retinopathy and a vision of normal individual is shown . Mona N.Alsaleem 2 Mohamed A. Berbar 1 437204273@student.ksu.edu.sa m_berbar@el-eng.menofia.edu.eg Faculty of Electronic Engineering, Menoufia University, Menouf 32952, Egypt. 1 King Saud University, Riyadh 11543, Saudi Arabia. 2